Conventionally, a social infrastructure (e.g. road and bridge, tunnel and underpass) is inspected periodically so that an aged position can be found and maintained through component replacement and reinforcement work. To conducting the periodic inspection, the operator goes to the social infrastructure to try to find an abnormal position through a visual inspection and a detailed technical inspection.
However, with the social development, more and more social infrastructures are built, and the number of infrastructures needing inspection is increased. In addition, after a social infrastructure is built, more and more positions are aged with the time elapsing, as a result, the positions in one social infrastructure needing inspection are increased. Thus, the supply of the periodic inspection carried out by operators cannot catch up with needs of the periodic inspection.
There is known a monitoring system which uses a camera arranged in a terminal facility of an emergency telephone at a roadside (for example, see Japanese Unexamined Patent Application Publication No. 2001-23075). In this system, each camera is used to capture the condition of each road and the captured image is sent to a center facility through a telephone line so that the condition of each road can be monitored by the center facility.